CHANGES IN STRUCTURE AND FUNCTION OF VENTRAL EPIDERMIS IN HYLA-ARBOREA-SAVIGNYI AUD (ANURA, HYLIDAE) THROUGHOUT METAMORPHOSIS

The changes in epidermal ultrastructure during the metamorphic cycle of Hyla arborea are described. The number of cell layers increased from two to four in the late tadpole stages. The cell layers flatten and the process of stratification reaches its peak after the completion of metamorphosis. The mitochondria-rich cell appears early in the tadpole stages. Numerous flask cells are noticeable in the post-metamorphic stages. K+-p-NPPase activity was localized cytochemically in the epidermis of H. arborea during its metamorphic cycle. In the epidermis of the legless tadpole, evidence for K+-p-NPPase activity was confined intracellularly. During the later tadpole stages, preceding metamorphic climax, the main ATPase activity shifted to the base-lateral cell membranes bordering with the intercellular spaces under the surface and later the stratum corneum. This continued after metamorphic climax in the juvenile toadlets, diminishing later in the adult stage.